janitor vs washing-up liquid

janitor

noun
  • Someone who looks after the maintenance and cleaning of a public building. 

  • A caretaker or custodian; someone who maintains a school building specifically and may serve other administrative roles. 

  • A doorman. 

  • A moderator for a discussion forum. 

washing-up liquid

noun
  • A form of liquid soap used to wash dishes by hand. 

How often have the words janitor and washing-up liquid occurred in a corpus of books? (source: Google Ngram Viewer )